Cannot unpickle polar plot #4068
Description
I create the polar plot example from http://matplotlib.org/examples/pie_and_polar_charts/polar_scatter_demo.html
Then
fig = plt.gcf()
pf = pickle.dumps(fig)
f2 = pickle.loads(pf)
throws the following exception:
/home/joerg/applications/anaconda3/lib/python3.4/site-packages/matplotlib/transforms.py in __setstate__(self, data_dict)
116 self.__dict__ = data_dict
117 # turn the normal dictionary back into a WeakValueDictionary
--> 118 self._parents = WeakValueDictionary(self._parents)
119
120 def __copy__(self, *args):
AttributeError: 'PolarAffine' object has no attribute '_parents'
Note that this is separate from issue #3483 in that plt.ioff() before unpickling does not work.